Landing cushion for falling objects

ABSTRACT

A device for decelerating an object in motion is provided with a first cushion body that is positioned within the path of travel of the object. This is a hollow, flexible and inflatable cushion provided with sidewalls, a supported surface, and a first surface. The supported and first surfaces are opposed, spaced apart and are disposed transversely of the path when the first cushion has been inflated. A hollow flexible and inflatable second cushion body is disposed in advance of the first cushion and has an impact surface and a second surface. The second cushion is supported by the first surface of the first cushion and has a higher gas pressure than the first cushion. The first surface of the first cushion and the impact surface of the second cushion are movable inwardly of the first and second cushions, respectively, when the bodies have been inflated, in response to the force of an object thereagainst. However, the second body is constructed to impede the rapid escape of gas upon the inward movement, thereby becoming relatively firm when the object strikes the impact surface. Thus, the area over which the force of the object is applied is greater on the first surface of the first cushion than the force area applied at the impact surface of the second cushion. Due to the relatively large force area, the gas pressure within the first body necessary to decelerate the object is decreased.

United States Patent 1 91 Morrison et a1.

[ LANDING CUSHION FOR FALLING OBJECTS [75] lnventors: Richard L. Morrison; Venard C.

Webb, both of Salina, Kans.

[73] Assignee: Thermo-Flex, lnc., Solina, Kans.

[22] Filed: Nov. 3, 1972 [21] Appl. No.: 303,324

[52] US. Cl. 5/350, 182/137 [51] Int. Cl. A47c 27/08 [58] Field of Search 5/348, 349, 350; 182/137, 182/139 [56] References Cited UNITED STATES PATENTS 3,391,414 7/1968 Gordon 5/348 R 3,513,491 5/1970 Gordon 182/137 X Primary ExaminerPaul R. Gilliam Assistant ExaminerAndrew M. Calvert Attorney, Agent, or Firm-Lowe, Kokjer, Kircher, Wharton & Bowman [57] ABSTRACT A device for decelerating an object in motion is pro- [4 1 Oct. 15, 1974 vided with a first cushion body that is positioned within the path of travel of the object. This is a hollow,'flexible and inflatable cushion provided with sidewalls, a supported surface, and a first surface. The supported and first surfaces are opposed, spaced apart and are disposed transversely of the path when the first cushion has been inflated. A hollow flexible and inflatable second cushion body is disposed in advance of the first cushion and has an impact surface and a second surface. The second cushion is supported by the first surface of the first cushion and has a higher gas pressure than the first cushion. The first surface of the first cushion and the impact surface of the second cushion are movable inwardly of the first and second cushions, respectively, when the bodies have been inflated, in response to the force of an object thereagainst. However, the second body is constructed to impede the rapid escape of gas upon the inward movement, thereby becoming relatively firm when the object strikes the impact surface. Thus, the area over which the force of the object is applied is greater on the first surface of the first cushion than the force area applied at the impact surface of the second cushion. Due to the relatively large force area, the gas pressure within the first body necessary to decelerate the object is decreased.

16 Claims, 13 Drawing Figures PATENTLUUCTISKUH SHEET 10F 3 &..

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4| 2 n n n n n u n n n n n u n n n n u PAT EMU-110m 1 51974 sum 30? 3 LANDING CUSHION FOR FALLING OBJECTS Support cylinders are provided at the edges of the first cushion body, supported surface. These support cylinders are hollow inflatable bodies in communication with the first body through restricted orifices. This assures that when an object pushes against the first body in'the area of the support cylinders, a higher gas pressure will be present in the cylinders than in the first body. Accordingly, the edges of the body will be supported and will not collapse.

It is well known that it is desirable to cushion the fall of pole vaulters and high jumpers in athletic contests without subjecting the athletes to shock or injury. Also, it has been found a desirable characteristic of these cushions to be portable, permitting quick and easy removal from the location of use to storage areas. Normally, this type air cushion applies a low initial gas pressure, with the pressure rapidly increasing as the athlete penetrates deeper into the cushion. It has therefore been thought desirable to have such an initial low gas pressure to softly cushion the initial shock of the falling vaulter and then increase the pressure to be sure the vaulter stops before bottoming out.

One such prior art device is shown in U.S. Pat. No. 3,399,407 issued Sept. 3, 1968. However, there are many characteristics of this type air cushion that make it unsatisfactory for use in athletic contests. One such characteristic is: if the electricity supplying the blower which provides the air pressure inside the cushion is removed, the cushion will lose pressure within approximately 3 seconds. Due to this rapidity of pressure loss, the cushion could fail to build sufficient pressure to completely decelerate the vaulter if the power is removed during a valt. Thus, serious injury could occur to the vaulter because of his impact with the ground, Another undesirable feature of this type of air cushion is the relatively far distance that the vaulter has to penetrate into the cushion before a sufficient air pressure is created therein for decelerating the vaulter. This deep penetration by the body of the vaulter with the corresponding sudden stop causd by the decelerating air pressure may generate a whiplash effect to the vaulter. This effect could be injurious or at best frightening to the vaulter. It has also been found that the safety wedges at the front of the air cushions of the patented device tend to twist a vaulters feet out from under him should he fall onto a wedge instead of onto the air cushion.

Accordingly, it is one of the primary objects of this invention to provide apparatus for decelerating moving objects using a relatively high pressure air cushion in advance of a lower pressure air cushion to widen the impact area of the object on the lower pressure cushion thus distributing the force of the object over a larger area and allowing the decelerating gas pressure to be relatively low at the moment of completion of the deceleration of the object.

Another aim of this invention is to eliminate a hard or slapping sensation caused by the tension in the material due to its relatively large radius of curvature as characterize the prior art devices. The construction of the second body of the present invention creates tufts of small radius, thereby reducing the tension and increasing its shock absorbing qualities. A body of this construction has been found to be far superior to pads of foamed rubber or polyurethane, or air cushions of the prior art.

Another primary object of this invention is to provide apparatus to decelerate moving objects when impacting an air cushion even upon removal of the electricity supplying the power to blowers providing the air pres sure to inflate the cushions.

A further object of this invention is to provide a sufficiently high gas pressure within the first, bottom air cushion to assist a vaulter in a relatively easy exit from the vaulting pit.

As a further object of this invention, an air cushion is constructed to cause a relatively high gas pressure to decelerate an object on initial impact thereby reducing the required pressure as the object penetrates deeper into the cushion.

Another aim of this invention is to provide front safety wedges in combination with an air cushion that will allow an object striking upon the impinging surfaces of these wedges to be impelled onto the impact surface without causing the vaulters feet to go out from under him.

As another aim of this invention, apparatus is provided to apply a relatively uniform decelerating force against an object striking an air cushion with a corresponding prevention of bounce to the object by controlling the variation in spacing between the top and bottom of the cushion.

Still another object of the invention is to provide support cylinders at the edges of the first cushion body, which cylinders are caused to have a higher gas pressure than the body when a force acts against the latter whereby the cylinder will support the edges of the body.

IN THE ACCOMPANYING DRAWINGS FIG. 1 is a front perspective view of the device of this invention;

FIG. 2 is an enlarged, fragmentary side elevational view of the device, a portion of the first inflatable body being broken away and appearing in cross-section to reveal details of construction;

FIG. 3 is an enlarged, fragmentary, vertical sectional view taken on line 3-3 of FIG. 2;

FIG. 4 is a fragmentary, vertical sectional view through the fan unit of the second body on a scale enlarged of FIG. 3, the fan blade and motor appearing in elevation;

FIG. 5 is a fragmentary, vertical sectional view through the blower unit in the same scale as FIG. 3, the one-way flap valve appearing in elevation;

FIG. 6 is an enlarged, fragmentary, elevational sectional view of a safety wedge and support, and showing the relationship between the orifice sizes communicating with a safety wedge;

FIG. 7 is a fragmentary, vertical sectional view taken on line 77 of FIG. 6 and on the same scale as FIG.

FIG. 8 is fragmentary, vertical sectional view taken on line 88 of FIG. 6 and on the same scale as FIG.

FIG. 9 is an enlarged, fragmentary, plan view of a portion of the second body;

FIG. 10 is an enlarged, fragmentary, vertical sectional view taken on line 10l0 of FIG. 9.

FIG. 11 is a perspective view of an alternative form of the invention showing the edge support cylinders;

FIG. 12 is an enlarged fragmentary end elevational view of the embodiment of FIG. 11 looking in the direction of arrows 12-12 and showing further details of the edge supports; and

FIG. 13 is a fragmentary vertical cross-sectional view of the cushion bodies and edge support taken along line 13-13 of FIG. 11.

Referring initially to FIGS. 13, a device includes a first inflatable body 22 in the nature of a hollow collapsible bag of flexible material. Body 22 has a bottom supported wall 24, a front wall 26 with forward extending walls 28 and front closing wall 30, a rear wall 32, sidewalls 34 and 36, and a first surface 38 the latter providing the top of body 22. The material from which body 22 is constructed is relatively impervious to the flow of air. A material such as nylon or the like which has been impregnated with rubber, neoprene, plastic or other synthetic material, is well-suited for this purpose. The joining of the walls to the individual surfaces may be by any suitable process such that the seam formed will be impervious to the flow of air.

A plurality of tabs 40 are secured in spaced intervals to the underside of top 38 and the upper surface of bottom 24. It may be seen from FIGS. 2 and 3 of the drawing that the tabs 40 for top 38 are located immediately above the corresponding tabs 40 for bottom 24. Cords 42 (constructed of inelastic material) and cords 44 (constructed of elastic material) are alternately secured to grommets 46 in tabs 40. When body 22 is inflated, cords 42 and 44 will stand substantially vertical between bottom 24 and top 38, thus the shape of body 22, when inflated with air, is substantially as shown in the drawings. A plurality of sandbag weights secured to walls 26, 30, 32 and 34 provide an anchoring system for the device 20.

A pair of auxiliary wedge shaped cushions 48 are secured to front closing wall 30 in mutually spaced relationship. As illustrated in FIGS. 6 and 7, each wedge 48 includes an impinging surface 50, a front wall 52, a backwall 54, an outside wall 56, an inside wall 57, and a support surface 58. Outside wall 56 of each wedge 48 is positioned substantially in a coplanar relation with forward extending wall 28, as shown in FIG. 1, and

back wall 54 is secured to front extending wall 30. The spacing between the inside walls 57 will be discussed in greater detail hereinafter.

A cord 60 is secured similarly to cords 42 and 44 in a relatively vertical position extending between impinging surface 50 and support surface 58 of each wedge 48. The relative spacing between surfaces 50 and 58 upon inflation of wedge 48 is maintained by cord 60. Each wedge 48 communicates with the interior of body 22 through orifices 62 for receiving air pressure.

Wedges 48 are each upheld by supporting cylinders 64, as illustrated in FIGS. 6 and 8. Each cylinder 64 comprises a hollow, inflatable, flexible, elongated member secured to support surface 58 of each respective wedge 48. Each cylinder 64 has an outside surface 66 and closing ends 68. Closing ends 68 and walls 56 and 57 of wedges 48 are in substantial alignment when viewed in a front, vertical direction (FIG. 8). Each supporting cylinder 64 communicates with the interior of the respective wedge 48 through surfaces 58 and 66 by means of relatively restricted orifices 70. Restrictive orifices 70 are substantially smaller than orifices 62 in back 54 of wedge 48 for purposes to be explained hereinafter.

Rear wall 32 of body 22 is provided with a port 72 which communicates with an elongated conduit 74, the

latter having one end secured to the angular rim of port 72 as best illustrated in FIG. 2. Conduit 74 may be of any convenient length and extends from rear wall 32 to an outlet 78 of blower unit 76. As seen in FIG. 5, blower 76 is of a conventional squirrel cage type with a protective casing 80 and an electric motor (not shown) providing the power to turn the blower blades (not shown). A one-way flap valve 82 is secured by its upper edge to blower outlet 78, such that, as long as air is being expelled from blower 76 through conduit '74, and into bag 22 the valve is open, as illustrated at 86. However, should the electricity to the motor of blower 76 be removed, the blower will cease to run and as the air tries to return through conduit 74, valve 82 closes and the air is prohibited from passing. Thus, the gas pressure within body 22 will be maintained for an extended period of time.

A second hollow, flexible, and inflatable body 86 is positioned atop and supported by first body 22. Second body 86 may be constructed of materials substantially similar to that used for the construction of first body 22. However, second body 86 is constructed differently from that of first body 22. That is, an impact surface 88 is used to form the top of second body 86 and is secured to a second surface 90, the latter providing the bottom for second body 86.. Impact surface 88 and second surface 90 are secured to a recurrent tufted pattern, such that a plurality of chambers 94, each characterized by an outer wall formed by surface 88 which is of a relatively small radius of curvature, are interconnected by air passages 96, as best seen in FIGS. 9 and 10. Second body 86 is held in a relatively fixed position to first surface 38 of body 22 by ties 98 and sandbag weights 106.

A conduit 100 is secured to the back portion of second body 86, as illustrated in FIGS. 1 and 2. Conduit 100 extends between second body 88 and a fan casing 102 mounted on the protective casing 80 of blower 76. Air is forced through conduit 100 by a blower fan 104 to inflate second body 86. The blower 184 is constructed to produce and maintain a relatively constant gas pressure in second body 86 higher than the gas pressure in first body 22.

Although, the device 20 has many applications for cushioning falling objects, it is particularly useful for athletic events such as pole vaulting and high jumping contests. When device 20 is to be used as a vaulting pit, the vaulting standards are placed on the outside of walls 28 and 56. Wedges 48 are positioned on either side of the vaulting box for placing the pole when the vaulter is vaulting, thus determining the distance between inside walls 57. Electrical wiring is run to the motors for fans 76 and 104. The fans are activated and bodies 22 and 86 are inflated to their respective gas pressures. First body 22 is inflated until spacers 42 and 44 limit the distance between support surface 24 and first surface 38, depending on the gas pressure produced by blower 76.

Upon activation of blower fan 104, air will be supplied through conduit 100, gas passages 96 and into the chambers 94, thus inflating second body 86. The fans 76 and 104 are controlled to provide a greater gas pressure in second body 86 than in first body 22. In general, it has been found that a satisfactory result is obtained when the pressure in second body 86 is from S to 10 inches water column and the pressure in first body 22 is from 1% to 1 /2 inches, of water column. Thus, when a vaulter impacts upon impact surface 88, impact surface 88 is compressed toward second surface 90. Because gas passages 96 are not continuous, the movement of gas from the impact area is delayed and only a minor amount of gas escapes through conduit 100 and blower 184 to the atmosphere. Therefore, second body 88 is essentially an enclosed air container with the air pressure acting within chamber 94 as a support to provide a relatively firm body. This distributing effect of the high pressure body 86 causes the force of the impacting object to be distributed over a larger area on first surface 38 than the actual contact area of the object on impact surface 88. Since second body 86 results in the force applied to body 22 being applied through a greater area, the gas pressure in first body 22 does not have to be as great to achieve the necessary deceleration as would be the case if an object were to strike first body 22 directly without first striking second body 86. This relatively fast application of a decelerating force aids in preventing the vaulter being rolled into a ball and becoming buried in the cushion. Also, the whiplash effect caused by a vaulters head penetrating substantially deeper into a low pressure cushion than the rest of his body is prevented. Since the distance the head lags behind the body is minor with bodies 22 and 86, movement of the head relative to the body is substantially eliminated.

As second surface 90 of second body 86 is compressed against first surface 38 of first body 22 through the force of the object on the impact surface 88, the gas pressure within first body 22 is increased and the flow of gas through conduit 74 tends to flow toward blower 76. This causes valve 82 to be closed, as illustrated in solid line on FIG. 5, thus prohibiting gas from leaving first body 22. Manifestly, valve 82 will close in a like manner when the electricity supplying the power to blowers 76 and l04-is removed. Since spacing cords 42 and 44 permit relative movement of surfaces 24 and 38, thus the force of an object impacting against body 22 causes only a relatively small pressure rise within body 22 even though it is essentially a closed container.

It has been found highly desirable to have spacing cords 42 and 44 alternately constructed of inelastic and elastic material, respectively. When all the cords are constructed of elastic material, first body 22 merely expands in the areas away from the impact area and sufficient pressure to completely decelerate the object is not developed, thus it may bottom out. When all the cords are constructed of relatively inelastic material, the surfaces 24 and 38 cannot move relatively and an undesired increase in pressure occurs as the object penetrates into the body. This may result in the object being decelerated too quickly for safety and/or comfort. However, it has been found by alternating inelastic and elastic cords, the undesired pressure increase is minimized without causing the object to be thrown or bounced" from the impacting surface.

The weight of sandbags 106 acting at edges 92 of second body 86 act in an inertial moment when the object impacts upon surface 88. That is, taking the sum of the moments about the contact area where the object impacts, the weights will tend to resist movement of impact surface 88 toward the impact area. This resistance aids in providing the second body 86 with relatively firm resistance to penetration by the object. Thus, through the use of these weights, a greater decelerating force is applied to the object more quickly to an object impacting on first surface 38.

Should the object miss the normal impact surface 88 of second body 86, and strike impinging surface 50 of wedges 48, impinging surface 58 will move inwardly toward support surface 58. The gas within wedge 48 is forced outwardly through orifices 62 and 70. The force of the object is then transmitted to supporting cylinder 64, which will accordingly cause a greater pressure within supporting cylinder 64 and there will be some tendency for gas to move from the cylinder into Wedge 48. However, since orifice '78 connecting the wedge with the cylinder is of much smaller diameter than orifice 62 connecting the wedge with body 22, a much larger amount of gas will escape from wedge 48 into first body 22 than will move from supporting cylinder 64 into wedge 48. Thus, the wedge 48 will move downwardly at the point of impact while the end of the wedge above cylinder 64 will remain substantially upright supported by the cylinder. The cylindrical crosssectional configuration of the wedge supports is highly desirable since any deformation of the cylinder will decrease the volume and increase the pressure, thus further contributing to support of wedge 48. This assures that a vaulter landing on a wedge and rolling toward bodies 22 and 86 will fall toward the cushion bodies rather than being thrown backwards onto the ground.

Referring now to FIGS. ll-l3 where an alternative embodiment of the invention is shown, a device designated generally by the numeral 128 is substantially identical to the device 20 described above except in the respects noted hereinafter. First cushion body 122 is provided with a supported surface 124 which is tapered upwardly at the edges of the body to present side wedges 108 of generally the same configuration as forward wedges 48 previously described.

As shown in FIG. 13, a plurality of auxiliary tie cords 142' (only one of which is visible in the drawing) hold supported surface 124 relative to the first or top surface 38 in the same manner as previously described for ties 42. It is to be understood that a plurality of ties 142 are spaced along the length of each side of body 122 other than the side from which wedges 48 project.

Disposed in underlying relationship to surfaces 38 and 124 at each side of body 122 other than the side from which wedges 48 project, is an elongated, hollow, flexible, inflatable edge support cylinder 164 of generally the same construction as cylinders 64 previously described. Cylinder 164 is in communication with the interior body 122 through one or more restricted orifices and will thus be inflated to a pressure normally equal to the pressure within the body 122 by blower 76.

While there have been previous attempts to provide high pressure areas around the perimeter of an air cushion to prevent collapse of the edges of the cushion such prior art devices have not been entirely satisfactory. A typical example of a prior art device of this type is shown in the patent to D. W. Gordan, Pat. No. 3,391,414, issued July 9, 1968. While this patentee proposed to have a high pressure area at the edge of his cushion, it was contemplated that this area would be maintained at a high pressure at all times thus necessitating an auxiliary air supply to maintain the high pressure. Since the air supply means is one of the major cost factors in constructing an air cushion, the high pressure area at the edge of this patentees cushion is achieved only at a substantial increase in cost. Also, the configuration of the high pressure areas which has characterized the prior art has resulted in their being deficient. When a configuration other than cylindrical is utilized, any deformation of the chamber defining the high pressure area will first result in an increase in volume of the area with no accompanying increase in pressure. Finally, the prior art devices have heretofore been characterized by completely underlying the cushion surface thus having little or no tendency to throw a person landing in the high pressure area toward the center of the cushion.

The foregoing disadvantages of the prior art devices are eliminated with the present invention. Since cylindrical supports 164 are in direct communication with the interior of body 122 and are inflated by blower 76 at the same gas pressure normally attributable to the first cushion body, no auxiliary blower is required to maintain the cylinder supports at a high pressure. On the other hand, because of the relatively restricted orifices between cylinders 164 and the interior of body 122, whenever an object moves against first surface 38 and thus exerts a force against cylinder 164, it will be much more difficult for air to escape from the cylinder than is the case from the impact area of body 122. Accordingly, a substantial pressure differential will develop between the support cylinders and the interior of the cushion body. This will cause the surface 38 to collapse while the cylinders 164 remain relatively firm and any object moving against the surface 38 in the vicinity of the cylinders will be thrown inwardly toward the center of body 122.

Another advantage of cylinders 164 is that. they are located so that a vertical bisector through the cylinder extends along a line adjacent to the edge of first surface 38. Thus, substantially one-half of the total area of each cylinder 164 is outside of the perimeter of top surface 38 further enhancing the support of the surface at its edges and assuring that an object striking the edge will actually be turned inwardly toward the center of the cushion. This is a substantial improvement in an air landing cushion which largely avoids the problem of collapsing edges.

While the invention has been described with particular reference to a pole vaulters landing cushion, it is to be understood that the invention can be utilized equally well in a high-jumping contest or other athletic events, as well as a safety device, and in fire rescue work.

Having thus described our invention, we claim:

1. A device for decelearating a person falling from an elevated height comprising:

a hollow, flexible, inflatable first body disposed within the path of travel of said person and adapted to have a gas pressure,

said first body including a supported surface and a first surface in opposed spaced apart relationship transversely of said path; and

a hollow, flexible, inflatable second body independent of the first body, disposed on said first surface and adapted to have a gas pressure at least three times the gas pressure in said first body,

said second body including an impact surface and a second surface in opposed spaced apart relationship and independent of said supported surface and said first surface;

whereby when a person impacts on said second body the impacting force is distributed over a relatively large area thereby decreasing the pressure needed in the first body to complete decelearation of the person.

2. The invention of claim 1, including alternating elastic and inelastic spacing members tying said supporting surface to said first surface from within said first body when the latter is inflated to control movement of said first surface in response to the force of a person thereagainst.

3. The invention of claim 1, wherein is included means for creating said gas pressures in said first and second bodies respectively.

4. The invention of claim 3, including a first conduit for communicating said first body with the gas pressure creating means; and means for controlling the flow of gas through the first conduit to maintain said first body in an inflated condition and preventing gas from leaving the body when a person impacts against it.

5. The invention of claim 4, wherein the gas pressure creating means comprises a first air blower communicating with the atmosphere with the first conduit, and said flow control means comprises a one way flap valve disposed downstream from said air blower.

6. The invention of claim 5, wherein is included a second conduit for communicating said second body with said gas pressure creating means, and the gas pressure creating means comprises a second air blower communicating with the atmosphere and disposed in communication with the second conduit.

7. The invention of claim 1, wherein said impact surface and said second surface are recurrently joined together to form a plurality of intercommunicated chambers in the second body.

8. The invention of claim 3, wherein said first body includes sidewalls combined with said supported and first surfaces; and including weight means coupled with said second body adjacent the sidewalls of the first body for generating a downward force near said sidewalls opposed to the force of a person moving against said first and impact surfaces whereby to provide increased resistance to the forces of the person.

9. The invention of claim 1, including:

a hollow, flexible, protective element combined with and projecting to one side of said first body and having a gas pressure, an impinging surface, and a support surface;

said impinging surface being movable toward said support surface in response to the force of a person moved thereagainst;

a hollow, flexible, inflatable support member underlying said impinging surface and having a gas pressure normally equal to the gas pressure in said element; and

means for causing the gas pressure in said member to become greater than the pressure in said element upon a person moving against the impinging surface of the element.

10. The invention of claim 9, wherein said means for causing a greater gas pressure in said protective element comprises a first opening communicating said elementwith said first body and a second opening communicating said element with said support member and having a smaller cross-sectional area than the first opening.

11. The invention of claim 10, wherein said support member is of circular cross-sectional configuration whereby to cause any deformation of the member to create a pressure increase therewithin.

12. The invention of claim 11, wherein a vertical bisector of said member extends along a line adjacent an edge of said impinging surface.

13. The invention of claim 1, wherein said device includes a hollow, flexible, inflatable edge support underlying said first surface at opposite edges of the latter to either side of the direction in which a person is jumping, said support having a normal gas pressure equal to the pressure in said first body; and means for causing the gas pressure in said support to become greater than 16. The invention of claim 15, wherein a vertical bisector of said support extends along a line adjacent to the edge of said first surface. 

1. A device for decelearating a person falling from an elevated height comprising: a hollow, flexible, inflatable first body disposed within the path of travel of said person and adapted to have a gas pressure, said first body including a supported surface and a first surface in opposed spaced apart relationship transversely of said path; and a hollow, flexible, inflatable second body independent of the first body, disposed on said first surface and adapted to have a gas pressure at least three times the gas pressure in said first body, said second body including an impact surface and a second surface in opposed spaced apart relationship and independent of said supported surface and said first surface; whereby when a person impacts on said second body the impacting force is distributed over a relatively large area thereby decreasing the pressure needed in the first body to complete decelearation of the person.
 2. The invention of claim 1, including alternating elastic and inelastic spacing members tying said supporting surface to said first surface from within said first body when the latter is inflated to control movement of said first surface in response to the force of a person thereagainst.
 3. The invention of claim 1, wherein is included means for creating said gas pressures in said first and second bodies respectively.
 4. The invention of claim 3, including a first conduit for communicating said first body with the gas pressure creating means; and means for controlling the flow of gas through the first conduit to maintain said first body in an inflated condition and preventing gas from leaving the body when a person impacts against it.
 5. The invention of claim 4, wherein the gas pressure creating means comprises a first air blower communicating with the atmosphere with the first conduit, and said flow control means comprises a one way flap valve disposed downstream from said air blower.
 6. The invention of claim 5, wherein is included a second conduit for communicating said second body with said gas pressure creating means, and the gas pressure creating means comprises a second air blower communicating with the atmosphere and disposed in communication with the second conduit.
 7. The invention of claim 1, wherein said impact surface and said second surface are recurrently joined together to form a plurality of intercommunicated chambers in the second body.
 8. The invention of claim 3, wherein said first body includes sidewalls combined with said supported and first surfaces; and including weight means coupled with said second body adjacent the sidewalls of the First body for generating a downward force near said sidewalls opposed to the force of a person moving against said first and impact surfaces whereby to provide increased resistance to the forces of the person.
 9. The invention of claim 1, including: a hollow, flexible, protective element combined with and projecting to one side of said first body and having a gas pressure, an impinging surface, and a support surface; said impinging surface being movable toward said support surface in response to the force of a person moved thereagainst; a hollow, flexible, inflatable support member underlying said impinging surface and having a gas pressure normally equal to the gas pressure in said element; and means for causing the gas pressure in said member to become greater than the pressure in said element upon a person moving against the impinging surface of the element.
 10. The invention of claim 9, wherein said means for causing a greater gas pressure in said protective element comprises a first opening communicating said element with said first body and a second opening communicating said element with said support member and having a smaller cross-sectional area than the first opening.
 11. The invention of claim 10, wherein said support member is of circular cross-sectional configuration whereby to cause any deformation of the member to create a pressure increase therewithin.
 12. The invention of claim 11, wherein a vertical bisector of said member extends along a line adjacent an edge of said impinging surface.
 13. The invention of claim 1, wherein said device includes a hollow, flexible, inflatable edge support underlying said first surface at opposite edges of the latter to either side of the direction in which a person is jumping, said support having a normal gas pressure equal to the pressure in said first body; and means for causing the gas pressure in said support to become greater than the pressure in said first body upon a person moving against said first surface in the area of said support.
 14. The invention of claim 13, wherein said support underlies said supported surface and is of circular cross-sectional configuration.
 15. The invention of claim 14, wherein said means for causing a greater gas pressure in the support comprises a restricted opening communicating the interior of said support with said first body.
 16. The invention of claim 15, wherein a vertical bisector of said support extends along a line adjacent to the edge of said first surface. 